The present invention relates to a vertical centrifugal pump unit, in particular for wet installation in a closed container, having an intermediate pipe which encloses the shaft of the unit and is arranged between the housing of the centrifugal pump and a bracket holding the electric motor of the pump unit, the pump unit being mounted on a flat horizontal part situated beneath the flange of the bracket, in particular on the cover of a container.
A pump unit of this type is known from U.S. Pat. No. 6,315,530. The intermediate pipe of this unit is provided with flanges by which it is attached with screws at one end to a corresponding flange on the bracket and at the other end to the pressure cover of the centrifugal pump housing. The flanges of such an intermediate pipe may be formed in one piece with the pipe body, if it is a cast part. Moreover, the flanges may be connected to a pipe by welding, although this increases the manufacturing cost. Regardless of how they are produced, all the ready-to-install intermediate pipes of this type have the disadvantage that they are adapted only to a certain shaft length. If such a centrifugal pump unit is constructed in different design lengths, then a separate casting mold is required for each length if the intermediate pipes are produced by casting. Adaptations to design lengths not provided previously are rendered difficult, if not impossible due, to the great complexity involved.